The purpose of the proposed investigation is two-fold. First, we wish to establish the most hospitable surface on the root which will allow attachment of human periodontal ligament fibroblasts and epithelial cells. Second, we wish to determine if any of the reported treatments for maintaining the viability of the PDL in avulsed teeth are effective in an in vitro system. That is, do milk, fluoridated milk, saliva or water keep the cells of the PDL alive and healthy when they are exposed to these media. We will test the ability of collagenase, trypsin, hyaluronidase, fibronection and acid etching to affect the attachment of cells to the root surface. We will allow radioactively labeled cells to attach to the root surface and quantitate their attachment by autoradiography. Once cells have attached we will assess their ability to remain attached and recover from treatment with milk, water etc. Further we will assess the quality of attachment by SEM and trypsinization procedures. Our goal is to develop via in vitro model, a treatment plan whereby avulsed teeth will stand the best chance of normal reattachment. This might involve letting epithelial and fibroblast cells attach to the root surface forming an artificial PDL. Our long term goal is to try and grow a new PDL on animal teeth and replant them, hopefully achieving normal reattachment and growth.